Precision boring machine

ABSTRACT

A machine for use in precision boring of elongated workpieces.

Unifie ta1es [191 [11] 3,73 2 Block et a1. 1 ay 1, 1973 1 PRECISIONBGRING MACHINE [76] Inventors: Forest E. Block, 4892 Spring Brook Road,Rockford, 111. 61 1 1 1; Ken- UN STATES PATENTS nelh E. Peterson, 822Hawthorne Avenue, Rockford, 111. 61 108 [22] Filed: N v. 1, 1 PrimaryExaminerLeonidas Vlachos pp NOJ 194,312 Att0meyJ. Maguire [56]References Cited 1,435,453 11/1922 Davis et al ..82/l2 [57] ABSTRACT[52] US. Cl ..82/l2 A machine for use in precision boring of elongated[51] Int. Cl. ..B23b 5/40 W0 k r pieces. [58] Field of Search..82/12;408/8, 31,

408/72, 236 4 Claims, 11 Drawing Figure Patented May 1, 1973 Fares? E.Block nefh E. Peierson BY Ken PRECISION BORING MACHINE This inventionrelates to an apparatus for use in generating an interior surface ofprecise revolution around the longitudinal axis of a workpiece having abore.

More particularly, this invention relates to an apparatus for use ingenerating an interior surface of a curve which is a circular arc ofradius R within the aforesaid bore of a workpiece.

In general, it is assumed that a workpiece to be finished with aninterior of desired configuration having precise dimensions is initiallyformed with a rough type bore by casting, forging and the like.

In the past, a precision finish could be imparted to the bore of aworkpiece usually by means of a contour lathe. In the latter device, theworkpiece is usually rotated relative to the lathe and the cutting meansis supported at one end but is movable in a controlled manner in atleast two mutually perpendicular rectilinear directions. The difficultywith the conventional device of this nature is that the desiredconfiguration of the cavity usually imposes restrictions on the size andshape of the holder and cutting means affixed thereto.

For instance, the holder of the cutting means is generally a relativelylong and narrow member which experiences a tremendous amount of straindue to the loading as the act of cutting is carried on at the extremityof the holder. In the past, for convenience, the holder was onlysupported at one end. As such, the load which the cutting device couldsustain with limited by the tendency of the holder to vibrate anddeflect from its intended position. Such vibrations or, as known in thetrade, chatter cause discontinuities in the surface being machined.Further deflection also causes the cutting means to occupy an undesiredlocation and, as a result, would produce an inaccurate surfaceconfiguration.

The above deficiencies of the art are more pronounced as the ratio ofthe length to the diameter of the holder is increased. Experience in thefield has shown that there are optimum ratios of the aforesaid factorswhich must not be exceeded to produce an acceptable product. Attemptshave been made to mitigate this problem, through the use of stiffermaterial or a reduction of the cutting load. However, this can only bedone by reducing the load on the cutting device or by reducing the feedrate of the tool. As a result, the latter action requires making aplurality of cutting passes to remove the required amount of metal toassure precision. All of the above, influences the production rate ofthe finished product by increasing the interval of time necessary tofinish one workpiece.

What is needed in the art is an apparatus for use in producing a desiredconfiguration or finish of precise dimension within the initially roughtype interior of a workpiece, the interior being in the form of alongitudinal passage of open end construction.

The subject invention answers the aforesaid needs of the art withoutencountering the difficulties of the conventional methods and apparatuswith special emphasis It is therefore an object of this invention toprovide an apparatus for use in generating an interior configurations ofprecise dimensions within the rough bore of a workpiece.

A further object is to provide an apparatus for use in the generating ofan interior surface of revolution around the longitudinal axis of arough cavity or bore of a workpiece.

Another object is to provide an apparatus for use in generating a curveof the aforesaid interior surface in the form of a circular arc ofvariable radius as desired along the longitudinal axis of suchworkpiece.

Other objects and many attendant advantages of this invention willbecome more apparent to one skilled in the art upon a reading of thefollowing detailed descriptions taken with the accompanying drawings,wherein:

The figure is a schematic view of the apparatus of this invention.

In the broad sense, the apparatus of this invention is provided with apivotal base in the horizontal plane having dual arms 12 and 13extending from such base 11 in same plane, each of which has attachedthereto a separate means 14 and 15 for supporting a cutting tool 16.Intermediate said first l4 and second 15 support means is a thirdsupporting means 17 for use in the axial rotation of a workpiece havinga rough bore or cavity 19 through which such cutting means 16 passes.

In this invention, the choice of the cutting means 16 and the attitudeof such means to the axially revolving workpiece 18 would determine theconfiguration, shape and precision of the finished cavity or bore of thefinal product.

in the narrow sense of the concept, the apparatus would comprise a base11 in the form of a flat plate of the U-shape variety having a first 14and second 15 supporting means in aligned relation to one another andpivotally movable with the arms 12 and 13 of such plate 11 to which theyare affixed. Intermediate the arms of the base and in operativealignment with the aforesaid supporting means is a third stationarysupporting means 17 adapted to provide axial rotation to said workpiece18. The first 14 and second I5 supporting means are adapted forlongitudinal movement to provide separable engagement of the cuttingtool by the first and second supporting means and access of the cuttingtool through the bore of the workpiece in the third supporting means.

In-the preferred embodiment, as shown, the base 11 is provided withpivotal point 20. The second support-- ing means 15 of the apparatus isin the form of a tool supporting head and the latter is adapted forlongitudinal movement transverse the arms 13 of the base 11. The headsupport 15 is driven in either longitudinal direction relative to thearm 15 by conventional means such as a cylinder and piston type fluidactuator. Power for driving such actuator could be preferably suppliedby a conventional oil hydraulic power unit which could include valvemeans for controlling the directions and speed of an actuator motion.

The supporting means 14 has a receptive open end 21 for receipt of theend of the elongated cutting tool 16 when inserted therein. The lattersupporting means 14 is provided with a conventional hydraulic systemwhich is initiated into providing gripping engagement against such toolend by the lateral movement of the tool in to the opening of thesupporting means 14. This lateral movement is initiated and provided bythe longitudinal movement of supporting means 15 towards the workpiece.

The above presupposes that the cutting tool 16 has passed through therough bore or cavity of the workpiece 18 and is now secured on eitherend by supporting means 14 and 15.

In operation the workpiece 18 is secured in position by supporting means17 and the cutting tool 16 is passed through the cavity or bore 19 bythe lateral movement of second supporting means 15. After passage of thetool through the bore 19 it is secured in position as heretoforeindicated.

At this point, the workpiece 18 may be revolved around its longitudinalaxis by the supporting means 17 through linkage 24 which communicateswith a source of motive force 25. Contact of the cutting tool 16 withthe interior surface of the workpiece to produce the preciseconfiguration desired is accomplished by cutting surfaces 27 whichrespond to the pivotal action of the base 11 and the movement of theextended arms 12 and 13.

Very exact and precise surfaces of a cavity may be produced by thisapparatus. Thus as the workpiece revolve, the cutting tool is moved inan arcuate manner relative to such bore a cavity in response to thepivotal movement of the base around pivot 20. To regulate the pivotalmovement of the base in order to achieve the optimum in duplicateconfiguration of precise dimension a regulator 30 is provided which maybe in the form of a hydraulic cylinder and piston.

in the manner described, the device of this invention has been found toproduce interior surface of very precise revolution around thelongitudinal axis of a workpiece having a bore. It has been found thatthis may be accomplished in an effective and efficient manner for theoptimization of the production of such precise workpieces in a minimumof time without encountering the deficiencies or difficulties of theart.

What is claimed is:

1. An apparatus for producing an interior surface of revolution aroundthe longitudinal axis of a bore or a workpiece comprising A basepivotally mounted in a plane said base having dual arms in the sameplane,

A first supporting means mounted on one of said arms,

A second supporting means mounted in fixed relation to the other of saidarms,

A third supporting means for said workpiece mounted in fixed relationbetween said first and second supporting means, said latter meansadapted to provide axial rotation to said workpiece, and

An elongated cutting tool passing through said workpiece and supportedby both said supporting means.

2. The apparatus of claim 1 wherein said first supporting means ismovable transverse said arm along a longitudinal axial path relative tosaid workpiece.

3. The apparatus of claim 1 wherein said second supaws? 23;aizirs slaztsrvases. auses-1 movement of said base is regulated to a circular arc ofa predetermined radius.

1. An apparatus for producing an interior surface of revolution aroundthe longitudinal axis of a bore or a workpiece comprising A basepivotally mounted in a plane said base having dual arms in the sameplane, A first supporting means mounted on one of said arms, A secondsupporting means mounted in fixed relation to the other of said arms, Athird supporting means for said workpiece mounted in fixed relationbetween said first and second supporting means, said latter meansadapted to provide axial rotation to said workpiece, and An elongatedcutting tool passing through said workpiece and supported by both saidsupporting means.
 2. The apparatus of claim 1 wherein said firstsupporting means is movable transverse said arm along a longitudinalaxial path relative to said workpiece.
 3. The apparatus of claim 1wherein said second supporting means is separably engaged to saidcutting tool.
 4. The apparatus of claim 1 wherein the pivotal movementof said base is regulated to a circular arc of a predetermined radius.